UNCULTURED Ã-PROTEOBACTERIA DOMINATE 16S RDNA CLONE LIBRARIES FROM NONYLPHENOL ETHOXYLATES- ENRICHED ACTIVATED SLUDGE

FIGUEROLA, EVA; ITRIA, RAÚL F.; LOZADA, MARIANA; ERIJMAN, LEONARDO

Bariloche, Argentina

Congreso; Congreso de la Sociedad Argentina de Investigaciones Bioquímicas (SAIB); 2003

Sociedad Argentina de Investigaciones Bioquímicas

Nonylphenol ethoxylates (NPEO) are widely used surfactants that enter the environment primarily through sewage and wastewater treatment plants, causing adverse effects on aquatic organisms. We investigated the link between bacterial population and NPEO biodegradation in engineered environments, using culturedindependent methods. Four clone libraries were constructed with amplified full-length insert 16S rDNA from reactors fed with synthetic effluent, two of which received additionally NPEO. A total of 187 clones were digested with restriction enzymes RsaI and HhaI. Changes of relative diversities under different treatment regimens, i.e. presence or absence of NPEO in the feeding solution, within otherwise identical environments, were taken as representative of qualitative changes in the microbial community. NPEO had a significant effect in the increase in relative abundance of a few RFLP patterns compared to control libraries. The sequences of several clones corresponding to the dominant phylotype in libraries from reactors treated with NPEO (ca. 35% of total clones in each replicate reactor) were assigned to uncultured gamma-proteobacteria subclass, suggesting the involvement of this group in NPEO degradation. Two new specific rRNA-targeted oligonucleotide probes were designed from our five 16S rDNA sequences and four other sequences retrieved from public databases of closely related environmental clones. Real time PCR using the specific probes demonstrated their applicability to monitoring the abundance of these so far uncultured species in natural and engineered environments.